1. Field of the Invention
The present invention relates to a composition for dyeing human keratin fibers, comprising at least one hydrophobic dye, at least one organic alkaline agent and/or at least one particular mineral base, at least one particular compound (I) and at least one particular organic compound (II), and also to a dyeing process.
2. Description of the Relevant Art
Two major methods for dyeing human keratin fibers, and in particular the hair, are known.
The first, known as oxidation dyeing or permanent dyeing, consists in using one or more oxidation dye precursors, more particularly one or more oxidation bases optionally combined with one or more couplers.
Oxidation bases are usually selected from ortho- or para-phenylenediamines, ortho- or para-aminophenols, and heterocyclic compounds. These oxidation bases are colorless or weakly colored compounds, which, when combined with oxidizing products, can give rise via a process of oxidative condensation to colored species, which remain trapped within the fiber.
The shades obtained with these oxidation bases are often varied by combining them with one or more couplers, these couplers being chosen especially from aromatic meta-diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds, such as indole compounds.
The variety of molecules used as oxidation bases and couplers allows a wide range of colors to be obtained.
Oxidation dyeing processes are generally performed by applying to keratin fibers oxidation dye precursors (one or more oxidation bases, optionally combined with one or more couplers) in the presence of an oxidizing agent, especially such as hydrogen peroxide (or aqueous hydrogen peroxide solution), which is mixed with the dye composition just before its use.
The resulting colorations are generally powerful and show good fastness especially with respect to shampooing.
However, the conditions of use are liable to lead to degradation of keratin fibers. In the long run, these fibers are more or less degraded and have a tendency to become coarse, dull, brittle and difficult to style, especially in the case of repeated dyeing.
The second dyeing method, known as direct dyeing or semi-permanent dyeing, comprises the application of direct dyes, which are molecules with affinity for the fibers and which color even in the absence of an oxidizing agent added to the compositions containing them. Given the nature of the molecules used, they tend rather to remain on the surface of the fiber and penetrate relatively little into the fiber, when compared with the small molecules of oxidation dye precursors.
The direct dyes generally used are chosen from nitrobenzene, anthraquinone, nitropyridine, azo, methine, azomethine, xanthene, acridine, azine and triarylmethane direct dyes. The chemical species used may be nonionic, anionic (acidic dyes) or cationic (basic dyes). Direct dyes may also be natural dyes.
The majority of the direct dyes used have sufficient solubility in aqueous medium, and numerous dye supports suitable for using them now exist.
These compositions containing one or more direct dyes are applied to keratin fibers for a time necessary to obtain the desired coloration, and are then rinsed out.
However, the colorations resulting therefrom are particularly chromatic colorations, but are, however, only temporary or semi-permanent since the nature of the interactions that bind the direct dyes to the keratin fiber and their desorption from the surface and/or the core of the fiber are responsible for their weak dyeing power and their poor fastness with respect to washing or to light.
Thus, the known processes for dyeing the hair, whether in the field of direct dyeing or oxidation dyeing, have room for improvement.
In particular, there is a need to provide processes for dyeing human keratin fibers that can respect the nature of these fibers and that in particular avoid their degradation, while at the same time affording powerful dyeing results, and being resistant to external agents, in particular to washing, perspiration, light, UV radiation, bad weather, rubbing and chemical treatments, such as permanent-waving treatments.
This need is in particular felt in the case of blue dyes, whose fastness with respect to light and to UV radiation is generally unsatisfactory.
To efficiently color keratin fibers, the majority of hydrophobic direct dyes must be used in the presence of particular solvents, whose role is to convey them into the fiber. Among the cosmetic solvents known for this purpose, aromatic solvents are frequently used. Mention may be made more particularly of benzyl alcohol, benzyloxyethanol or phenoxyethanol.
However, the presence of the aromatic solvents, which are sparingly soluble in aqueous medium, makes it necessary to use large amounts of cosolvents, usually ethanol, in order to make them compatible with standard dye formulations.
Moreover, even under these conditions, the intensity of the colorations obtained remains insufficient or the selectivity remains too high.
In addition, reducing agents such as hydrosulfites are occasionally used in the textile field, in order to reduce reducible hydrophobic dyes. However, these compounds are harmful to the environment, and especially contaminate the waste water extensively. Moreover, they give off very unpleasant odors, which make them unsuitable for use in the cosmetics field.
There is thus a need to provide novel compositions based on hydrophobic dyes for dyeing human hair, which are more efficient, while at the same time being compatible with hydrophobic dyes, and which respect both the environment and the nature of the hair. These compositions must also make it possible to obtain powerful, unselective and resistant dyeing results.
Patent application FR 2 771 286 in the name of the Applicant describes, in general, the use of compounds of indigoid type in cosmetic compositions, and more particularly in makeup compositions such as lipsticks, foundations, face powders, eyeshadows, loose or compact powders, eyeliners, mascaras and nail varnishes.